Recurrent Abscesses, Scarring, and Sinus Tract Formation: The Clinical Presentation of Hidradenitis Suppurativa

Sara M. James, MD, and Barbara B. Wilson, MD

The first of a 4-part series outlines the clinical presentation of hidradenitis suppurativa, including appearance, characteristic lesions, and differential diagnosis.

ABSTRACT: Hidradenitis suppurativa (HS) is a chronic disease presenting with recurrent abscesses, scarring, and sinus tract formation. The condition is most common in the intertriginous areas, including the axillae, groin, and perineal area. Its pathophysiology is not completely understood, but follicular occlusion is believed to be the key pathologic event. Bacterial infection is likely a secondary feature of the disease. Treatment of HS varies with disease severity. Mild disease can be treated with topical antibiotics, but systemic antibiotics, hormonal therapies, laser therapy, and biologic agents are used to treat more severe or refractory disease. Surgery is required for definitive treatment. Patients with HS experience pain and embarrassment and are more likely to experience depression. In this 4-part series, the authors provide an overview of HS, detailing its clinical presentation, grading systems used to score HS severity, the pathophysiology of the disease, and methods of treatment.

Hidradenitis suppurativa (HS) is a chronic disease presenting with recurrent, painful nodules and abscesses that heal with scarring, sinus tract formation, and fistulae (Figure 1). Estimates of prevalence range from 0.053% to 4.1%.1,2 However, the disease is likely underreported, because patients feel embarrassed and are hesitant to seek medical help.3 HS is often misdiagnosed as furunculosis or “boils.”4 Although the pathogenesis is not fully understood, the prevalent theory posits that HS is caused by occlusion of the terminal portion of the hair follicle.5 HS is not caused by poor hygiene and is not contagious.

HS is also known as acne inversa, because it has a predilection for the intertriginous or inverse areas, classically the axillae, groin, inguinal folds, inner thighs, mammary and inframammary areas, and buttocks.6 However, the term acne inversa is a misnomer, because HS is not a type of acne. Although hyperkeratosis of the hair follicle occurs in both conditions, HS involves the deep part of the follicle rather than superficial part, and there is no hyperseborrhea or change in density or activity of the sebaceous glands.7 HS is psychologically and physically debilitating, given that the lesions are painful and that patients are embarrassed by the location of the lesions and the chronic, malodorous drainage.3

Clinical Presentation

The diagnosis of HS is based on clinical appearance and history. Skin biopsy is rarely needed for diagnosis but may be required if there is suspicion for malignancy.8 Criteria for diagnosis include classic localization of disease (axillae and groin), a chronic, relapsing course, and the presence of deep-seated, painful nodules and abscesses with or without sinus tracts and scarring.7 When considering the diagnosis of HS, the differential diagnosis should also include granuloma inguinale, Crohn disease, acne, actinomycosis, inflamed epidermal cysts, and staphylococcal abscesses.

Onset of disease occurs anytime after puberty until 40 years of age but is most common in the second and third decades of life. The disease may remit after menopause in women. HS affects women more often than men, with a 1 to 3 ratio.7 The axillae (most common location), groin, and inner thighs are affected in both men and women. Women are more likely to have upper torso involvement, whereas men more often have gluteal or perianal disease (Figure 2).9 Disease is common in both sexes at sites of increased friction, such as the beltline or bra strap.

The characteristic lesions begin as inflammatory, painful, deep nodules. Some nodules heal spontaneously, while others expand and merge with adjacent nodules to form coalescing lesions, which can rupture and drain seropurulent fluid.8 Drainage of fluid relieves the pain, but lesions usually recur. Longstanding HS results in the formation of scarring, contractures, and interconnected sinus tracts that may drain fluid. Scarring can range from small, atrophic scars to thick, fibrotic tracks.4 Large, multiheaded, open comedones are the end stage of damage and represent loss of the sebaceous gland and hair follicle.10

Longstanding HS is associated with a number of complications. Squamous cell carcinoma (SCC) can develop within scars in patients who have had the disease an average of 25 years.5 Case reports have attributed a number of deaths of HS patients to metastatic SCC. It is hypothesized that the constant inflammation of HS results in metaplasia and carcinoma formation, which can be difficult to identify against the background of scarring and sinus tracts.6 Extensive scarring in the groin can cause lymphatic obstruction and vulvar or scrotal lymphedema (Figure 3).11,12 Strictures and contractures may limit movement.5 Anemia has also been noted in a number of patients with HS.13 Osteomyelitis and epidural abscesses are the most serious consequences of secondary bacterial infection of the skin lesions.14,15


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